In a circuit breaker, current transformers are used to continuously sense the current level and to trip the circuit breaker when the rated current level is exceeded. Whether they are in toroidal or laminated form, the current transformers within a circuit breaker provide a continuous sample of the current level to the electronic trip unit. One example of a current transformer used within circuit breaker electronic trip units is found in U.S. Pat. No. 3,449,703 entitled "Current Transformer Having an Accuracy Unimpaired by Stray Flux Adjacent Conductors". A further example is found in U.S. Pat. No. 4,591,942 entitled "Current Sensing Transformer Assembly".
Using a single iron core current transformer with multiple windings to both sense the circuit current and provide operating power to the electronic trip unit provides the advantage of reducing bulky components and conserving space which is often limited in a molded case circuit breaker. Solid state devices, such as a Hall Effect transducer can also help conserve space, however, to date, the use of a solid state device has not proven feasible as a current sensor because of its poor performance and inaccuracy in sensing the current level. Examples of a Hall effect current sensor are found in U.S. Pat. No. 3,621,334 entitled "Ground Fault Sensing Circuit" and U.S. Pat. No. 5,196,982 entitled "Electrical Power Monitoring System". Accordingly, it would be highly desirable to have a current sensor that uses a solid state device to provide a sensing signal that accurately reflects the current level in the circuit breaker.